Area Forecast Discussion
Issued by NWS Wilmington, NC

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000 FXUS62 KILM 280607 AFDILM AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON NC 207 AM EDT MON JUL 28 2014 .SYNOPSIS... OPPRESSIVE HEAT AND HUMIDITY WILL CONTINUE THROUGH MONDAY. A STRONG COLD FRONT WILL CROSS THE AREA MONDAY NIGHT...BRINGING A GOOD CHANCE FOR THUNDERSTORMS...SOME OF WHICH MAY BE SEVERE. MUCH DRIER AND UNSEASONABLY COOL AIR WILL OVERSPREAD THE CAROLINAS BEGINNING ON TUESDAY...AND PERSISTING INTO THE WEEKEND. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... AS OF 10:15 PM SUNDAY...REMNANTS OF A LARGE CONVECTIVE COMPLEX APPROACHING THE FORECAST AREA THIS EVENING. AT THE VERY LEAST WE WILL SEE A THICKENING OF THE CLOUD COVER. ON THE FENCE WHETHER WE WILL SEE ANY SPRINKLES FROM IT. THE HRRR HINTS AT SOME LIGHT RAIN FROM AROUND MIDNIGHT OR SO OVER OUR NORTHERNMOST FRINGES. IN ANY CASE THIS LOOKS LIKE A LOW IMPACT EVENT...WITH ANY POSSIBLE PRECIP IN THE FEW HUNDREDTHS OF AN INCH RANGE. WILL MONITOR PROGRESSION OF THIS FEATURE AND UPDATE AS IT BECOMES CLEARER AS TO ITS STAYING POWER. RELEVANT PORTION OF PREVIOUS DISCUSSION FOLLOWS: LINGERING WARMTH AND MARITIME HUMIDITY WILL MAKE FOR BALMY NIGHT TIME CONDITIONS AND AM EXPECTING MANY LOCATIONS ALONG AND NEAR THE SEA/ICW TO REMAIN ABOVE 80 DEGREES EVEN INTO DAYBREAK MONDAY...AND MINIMUMS HAVE BEEN PAINTED TO REFLECT THIS EXCEPTIONALLY MILD AIR IN THE NEAR TERM PERIOD. DRY AND WARM AIR ALOFT WILL PUT A LID ON RAIN CHANCES THROUGH EARLY MONDAY. A FEW SHOWERS ARE EXPECTED OFFSHORE BUT LOOKS LIKE THEY WILL REMAIN WELL ENOUGH OUT TO SEA TO AVOID IMPACTING CAPE FEAR INTO DAYBREAK MONDAY. && .SHORT TERM /6 AM THIS MORNING THROUGH TUESDAY NIGHT/... AS OF 300 PM SUNDAY...A STRONG COLD FRONT WILL SWEEP ACROSS THE FORECAST AREA LATE MONDAY...BRINGING AN INCREASING THREAT OF STRONG TO SEVERE THUNDERSTORMS MONDAY AFTERNOON INTO THE EVENING HOURS. UNSEASONABLY COOLER AND DRIER AIR WILL SPILL SOUTHWARD INTO THE CAROLINAS ON TUESDAY FOLLOWING FROPA. MONDAY LOOKS LIKE ANOTHER HOT AND HUMID DAY WITH DEEP WESTERLY FLOW ALOFT AND STRENGTHENING SOUTHWEST WINDS AT THE SURFACE. 850 MB TEMPS REMAIN IN THE 20C RANGE...GIVING ANOTHER DAY WITH FORECAST HIGHS IN THE MID/UPPER 90S. WITH DEWPOINTS IN THE LOW TO MID 70S...HEAT INDEX VALUES WILL ONCE AGAIN CLIMB ABOVE TRIPLE DIGITS ACROSS THE AREA. A HEAT ADVISORY HAS BEEN ISSUED ACROSS OUR SOUTHERN ZONES...FROM FLORENCE TO MARION TO HORRY COUNTY AND SOUTHWARD...WITH HEAT INDEX VALUES FORECAST TO EXCEED 105F. ELSEWHERE...EXPECT HEAT INDICES IN THE 100-104F RANGE. TSTM CHANCES INCREASE AFTER 18Z AS A NARROW RIBBON OF DEEPER MOISTURE AHEAD OF THE FRONT MOVES INTO THE EASTERN CAROLINAS. SURFACE CAPE VALUES OF 2500-3000 J/KG AND 35-40 KT OF 0-6 KM BULK SHEAR DEPICT AN ENVIRONMENT CAPABLE OF SUPPORTING MULTI-CELLS WITH ISOLATED SUPERCELLS POSSIBLE. THE LIMITING FACTORS WOULD BE UPSTREAM DEBRIS CLOUD COVER SLOWING THE RATE OF SFC HEATING EARLIER IN THE DAY...AS WELL AS A LACK OF WIDESPREAD DEEP MOISTURE. THE STORM PREDICTION CENTER HAS MAINTAINED A DAY 2 SLIGHT RISK FOR THE MAJORITY OF OUR CWA. FORECAST DCAPE VALUES > 1000 J/KG AND HEALTHY CAPE IN THE HAIL GROWTH ZONE MAKE DAMAGING WINDS AND SEVERE HAIL THE PRIMARY THREATS. THE BEST WINDOW FOR SCATTERED STRONG TO SEVERE CONVECTION BASED ON THE TIMING OF THE FRONT LOOKS TO BE BETWEEN 18-00Z. EXPECT TSTMS WILL BECOME ORGANIZED INTO A LINE AS THEY MOVE ACROSS THE AREA AND OFFSHORE BY MONDAY NIGHT. THE COLD FRONT WILL PUSH OFFSHORE OVERNIGHT MONDAY...BRINGING COOLER AND DRIER CONDITIONS FOR TUESDAY. NORTHERLY FLOW WILL PERSIST DURING THE DAY AS HIGHS WILL ONLY REACH THE MID 80S. OVERNIGHT LOWS WILL DIP INTO THE MID 60S AWAY FROM THE BEACHES. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... AS OF 300 PM SUNDAY...COLD FRONT WELL OFFSHORE WILL STALL THROUGH THE WEEK AS ANOMALOUS 500MB TROUGH BECOMES NEARLY STATIONARY ACROSS THE EASTERN CONUS. AS THE TROUGH AXIS REMAINS WEST OF THE AREA THROUGH THE END OF THE WEEK...MID-LEVELS WILL REMAIN DRY AS EVIDENCED BY PWATS OF 1-1.25 INCHES THROUGH FRIDAY...WHICH COMBINED WITH NE FLOW KEEPING TEMPS A SOLID 5-8 DEGREES BELOW CLIMO...WILL LIMIT POP COVERAGE AND EXPECT A DRY WEEK. AS MENTIONED BY PREVIOUS FORECASTER...WEAK IMPULSES ALOFT ROTATING THROUGH THE BASE OF THE LONGWAVE TROUGH COULD SPAWN ISOLATED SHOWERS THU/FRI...BUT TIMING THESE ON D5/D6 IS NEARLY IMPOSSIBLE...AND WITH THE COLUMN REMAINING DRY WILL OPT TO KEEP FORECAST POP AT SILENT. BY THE WEEKEND...THE ECMWF AND GFS BEGIN TO DIVERGE IN THEIR SOLUTIONS...BUT THE GENERAL TREND IS THAT THE RIDGE ACROSS THE ATLANTIC WILL EXPAND WESTWARD...FORCING THE TROUGH TO RETROGRADE. WHILE THIS WILL BRING A RETURN TO TEMPS CLOSER TO NORMAL VALUES LATE IN THE PERIOD...MOISTURE WILL INCREASE AS WELL AND WILL RAMP POP UP TO CHC FOR THE WKND AS THE STALLED FRONT/COASTAL TROUGH MOVES BACK TOWARDS THE COAST. ALL 3 OF THE EXTENDED OPERATIONAL MODELS...GFS/ECM/CMC...SUGGEST LOW PRESSURE MAY DEVELOP ALONG THIS BOUNDARY NEXT WEEKEND FURTHER ENHANCING THE RAINFALL POTENTIAL. WILL NOT SHOW ANYTHING BUT HIGHER POP IN THE FORECAST FOR D7...BUT IT IS SOMETHING WORTH WATCHING DURING THE UPCOMING DAYS. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... AS OF 06Z...A DYING MCS/MCC WELL UPSTREAM BOOKING ESE COULD REACH THE INLAND TERMINALS BEFORE DISSIPATING ALTOGETHER. HAVE INCLUDED VICINITY CONVECTION TO ACCOMODATE. MAINLY MID-UPPER LEVEL CONVECTIVE DEBRIS CLOUDINESS WILL PUSH ACROSS THE AREA TERMINALS DURING THIS MORNING...THINNING OUT AFTER DAYBREAK. THE CLOUDINESS AND SFC WINDS AT 5 TO 10 KT WILL BOTH KEEP ANY FOG FROM DEVELOPING THIS AM. FOR DAYTIME INTO EARLY EVENING MONDAY...THE ATMOSPHERE WILL MOISTEN UP MAINLY THE LOWER LEVELS WITH PROGGED PWS AROUND 2 INCHES...AND FURTHER BECOME UNSTABLE AHEAD OF AN APPROACHING COLD FRONT. THE FRONT WILL PUSH ACROSS THE TERMINALS FROM NW TO SE FROM LATE THIS AFTERNOON INLAND...AND OFF THE COAST EARLY THIS EVENING. TIGHTENED SFC PG AND OVERALL STRONG WINDS ALOFT WILL PREVENT ANY INLAND PROGRESSION OF THE SEA BREEZE. THUS...LOOKING AT 240-270 DEGREES WINDS AROUND 15 KT WITH GUSTS TO 20 KT. ISOLATED TO SCATTERED STRONG CONVECTION AHEAD OF THE FRONT REMAINS A POSSIBILITY...AND HAVE HIGHLIGHTED ITS OCCURRENCE ACROSS THE TERMINALS. AFTER FROPA...THREAT FOR CONVECTION WILL CEASE AND WINDS TO VEER TO THE NW AT 10 KT OR LESS. EXTENDED OUTLOOK...MORNING FOG POSSIBLE THURSDAY AND FRIDAY...OTHERWISE VFR. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 10:15 PM SUNDAY...NO CHANGES TO THE FORECAST WITH THE LATEST UPDATE. PREVIOUS DISCUSSION FOLLOWS: BUMPY MARINE CONDITIONS WILL DEVELOP TONIGHT AND PERSIST THROUGH MONDAY DUE TO STIFF SW WINDS AHEAD OF AN APPROACHING AND UNSEASONABLY STRONG COLD FRONT. FOR TONIGHT INTO SUNRISE MONDAY...SW WINDS OF 15-20 KT AND 3-5 FOOT SEAS WILL PREVAIL...PROMPTING THE CAUTION STATEMENT. THE SEA SPECTRUM WILL FEATURE SSW WAVES 2-4 FEET EVERY 4-6 SECONDS...AND SE WAVES 1-1.5 FR EVERY 9 SECONDS. SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 300 PM SUNDAY...THE PERIOD WILL BEGIN WITH SCEC CONDITIONS AS SOUTHWEST WINDS STRENGTHEN TO 15-20 KT WITH OCCASIONAL GUSTS UP TO 25 KT AHEAD OF AN APPROACHING COLD FRONT. SEAS WILL BE 3-5 FT... BECOMING 4-6 FT ACROSS THE FAR OUTER PORTIONS OF AMZ250/252 BY MONDAY EVENING. MARGINAL SCA CONDITIONS MAY WARRANT A HEADLINE TOMORROW...BUT CONFIDENCE IS STILL TOO LOW TO RAISE IT TODAY. WINDS WILL SHIFT OVERNIGHT AS THE COLD FRONT PUSHES OFFSHORE...BECOMING WEST AROUND 10 KTS AFTER MIDNIGHT AND THEN NORTH AROUND 10 KTS BY TUESDAY MORNING. SEAS WILL SUBSIDE ON TUESDAY WITH THE LIMITED NORTHERLY FETCH...BECOMING 2-3 FT BY THE END OF THE PERIOD. LONG TERM /WEDNESDAY THROUGH FRIDAY/... AS OF 300 PM SUNDAY...PRETTY UNIFORM WIND/WAVE CONDITIONS THROUGH THE EXTENDED AS COLD FRONT STALLS WELL OFFSHORE AND SURFACE HIGH PRESSURE RIDGES DOWN THE COAST. THIS LEAVES E/NE WINDS THROUGH THE PERIOD WITH LITTLE FLUCTUATION...AND SPEEDS WITHIN A FEW KTS OF 10 BOTH DAY AND NIGHT. ALTHOUGH A WEAK SE GROUND SWELL WILL EXIST IN THE WAVE SPECTRUM...SEAS OF 2-3 FT EACH DAY WILL BE FORMED PRIMARILY FROM AN EASTERLY 4 SEC WIND CHOP. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...HEAT ADVISORY FROM 11 AM THIS MORNING TO 6 PM EDT THIS EVENING FOR SCZ032-033-039-053>056. NC...NONE. MARINE...NONE. && $$ SYNOPSIS...JDW NEAR TERM...MJC/REK SHORT TERM...BJR LONG TERM...JDW AVIATION...DCH

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